\ProvidesPackage{evan}
\usepackage{amsmath,amssymb}
%%fakesection Argument processing
% Default Arguments
% We include "Evan" in all of these to make sure
% that they don't collide with anything in external packages
\newif\ifevanfancy\evanfancytrue
\newif\ifevanhdr\evanhdrtrue
\newif\ifevanhref\evanhreftrue
\newif\ifevansetup\evansetuptrue
\newif\ifevanthm\evanthmtrue
\newif\ifevansecthm\evansecthmfalse
\newif\ifevanht\evanhtfalse
\newif\ifevanpkg\evanpkgtrue
\newif\ifevanpdf\evanpdftrue
\newif\ifevantitling\evantitlingtrue
\newif\ifevanauthor\evanauthortrue
\newif\ifevanchinese\evanchinesefalse
\newif\ifevanmdthm\evanmdthmfalse
\newif\ifevandiagrams\evandiagramsfalse
\newif\ifevanpatchasy\evanpatchasyfalse
\newif\ifevanhints\evanhintsfalse
\newif\ifevanasy\evanasytrue
\newif\ifevancolorsec\evancolorsecfalse
\newif\ifevantitlemark\evantitlemarktrue

%Receive Arguments
\DeclareOption{chinese}{\evanhreffalse\evanchinesetrue} % Chinese support
% allow href to override this one

\DeclareOption{sexy}{\evansecthmtrue\evanmdthmtrue\evancolorsectrue} % long docs

\DeclareOption{fancy}{\evanfancytrue}
\DeclareOption{nofancy}{\evanfancyfalse}
\DeclareOption{hdr}{\evanhdrtrue}
\DeclareOption{nohdr}{\evanhdrfalse}
\DeclareOption{href}{\evanhreftrue}
\DeclareOption{nohref}{\evanhreffalse}

\DeclareOption{nosetup}{\evansetupfalse}
\DeclareOption{thm}{\evanthmtrue}
\DeclareOption{nothm}{\evanthmfalse}
\DeclareOption{secthm}{\evansecthmtrue}
\DeclareOption{nosecthm}{\evansecthmfalse}

\DeclareOption{ht}{\evanhttrue}
\DeclareOption{nopdf}{\evanpdffalse}
\DeclareOption{nopkg}{\evanpkgfalse}
\DeclareOption{oldtitle}{\evantitlingfalse}
\DeclareOption{newtitle}{\evantitlingtrue}
\DeclareOption{noauthor}{\evanauthorfalse}
\DeclareOption{titlemark}{\evantitlemarktrue} % Sets title in ohead, not \rightmark
\DeclareOption{sectionmark}{\evantitlemarkfalse} % Uses \rightmark not title in ohead

\DeclareOption{mdthm}{\evanmdthmtrue}
\DeclareOption{nomdthm}{\evanmdthmfalse}
\DeclareOption{diagrams}{\evandiagramstrue}
\DeclareOption{nodiagrams}{\evandiagramsfalse}
\DeclareOption{colorsec}{\evancolorsectrue}
\DeclareOption{nocolorsec}{\evancolorsecfalse}

\DeclareOption{patchasy}{\evanpatchasytrue}
\DeclareOption{noasy}{\evanasyfalse}

\DeclareOption{hints}{\evanhintstrue}

\ProcessOptions\relax

% if packages not loaded, turn off mdthm and asy
\ifevanpkg\else\evanmdthmfalse\fi
\ifevanpkg\else\evanasyfalse\fi

% If no setup, turn off theorems
\ifevansetup\else\evanthmfalse\fi

%%fakesection Some macros
%Small commands
\newcommand{\cbrt}[1]{\sqrt[3]{#1}}
\newcommand{\floor}[1]{\left\lfloor #1 \right\rfloor}
\newcommand{\ceiling}[1]{\left\lceil #1 \right\rceil}
\newcommand{\mailto}[1]{\href{mailto:#1}{\texttt{#1}}}
\newcommand{\ol}{\overline}
\newcommand{\ul}{\underline}
\newcommand{\wt}{\widetilde}
\newcommand{\wh}{\widehat}
\newcommand{\eps}{\varepsilon}
%\renewcommand{\iff}{\Leftrightarrow}
%\renewcommand{\implies}{\Rightarrow}
\newcommand{\vocab}[1]{\textbf{\color{blue} #1}}
\newcommand{\catname}{\mathsf}
\newcommand{\hrulebar}{
  \par\hspace{\fill}\rule{0.95\linewidth}{.7pt}\hspace{\fill}
  \par\nointerlineskip \vspace{\baselineskip}
}
\newcommand{\half}{\frac{1}{2}}

%For use in author command
\newcommand{\plusemail}[1]{\\ \normalfont \texttt{\mailto{#1}}}

%More commands and math operators
\DeclareMathOperator{\cis}{cis}
\DeclareMathOperator*{\lcm}{lcm}
\DeclareMathOperator*{\argmin}{arg min}
\DeclareMathOperator*{\argmax}{arg max}

%Convenient Environments
\newenvironment{soln}{\begin{proof}[Solution]}{\end{proof}}
\newenvironment{parlist}{\begin{inparaenum}[(i)]}{\end{inparaenum}}
\newenvironment{gobble}{\setbox\z@\vbox\bgroup}{\egroup}

%Inequalities
\newcommand{\cycsum}{\sum_{\mathrm{cyc}}}
\newcommand{\symsum}{\sum_{\mathrm{sym}}}
\newcommand{\cycprod}{\prod_{\mathrm{cyc}}}
\newcommand{\symprod}{\prod_{\mathrm{sym}}}

%From H113 "Introduction to Abstract Algebra" at UC Berkeley
\newcommand{\CC}{\mathbb C}
\newcommand{\FF}{\mathbb F}
\newcommand{\NN}{\mathbb N}
\newcommand{\QQ}{\mathbb Q}
\newcommand{\RR}{\mathbb R}
\newcommand{\ZZ}{\mathbb Z}
\newcommand{\charin}{\text{ char }}
\DeclareMathOperator{\sign}{sign}
\DeclareMathOperator{\Aut}{Aut}
\DeclareMathOperator{\Inn}{Inn}
\DeclareMathOperator{\Syl}{Syl}
\DeclareMathOperator{\Gal}{Gal}
\DeclareMathOperator{\GL}{GL} % General linear group
\DeclareMathOperator{\SL}{SL} % Special linear group

%From Kiran Kedlaya's "Geometry Unbound"
\newcommand{\abs}[1]{\left\lvert #1 \right\rvert}
\newcommand{\norm}[1]{\left\lVert #1 \right\rVert}
\newcommand{\dang}{\measuredangle} %% Directed angle
\newcommand{\ray}[1]{\overrightarrow{#1}} 
\newcommand{\seg}[1]{\overline{#1}}
\newcommand{\arc}[1]{\wideparen{#1}}

%From M275 "Topology" at SJSU
\newcommand{\id}{\mathrm{id}}
\newcommand{\taking}[1]{\xrightarrow{#1}}
\newcommand{\inv}{^{-1}}

%From M170 "Introduction to Graph Theory" at SJSU
\DeclareMathOperator{\diam}{diam}
\DeclareMathOperator{\ord}{ord}
\newcommand{\defeq}{\overset{\mathrm{def}}{=}}

%From the USAMO .tex filse
\newcommand{\st}{^{\text{st}}}
\newcommand{\nd}{^{\text{nd}}}
\renewcommand{\th}{^{\text{th}}}
\newcommand{\dg}{^\circ}
\newcommand{\ii}{\item}

% From Math 55 and Math 145 at Harvard
\newenvironment{subproof}[1][Proof]{%
\begin{proof}[#1] \renewcommand{\qedsymbol}{$\blacksquare$}}%
{\end{proof}}

\newcommand{\liff}{\leftrightarrow}
\newcommand{\lthen}{\rightarrow}
\newcommand{\opname}{\operatorname}
\newcommand{\surjto}{\twoheadrightarrow}
\newcommand{\injto}{\hookrightarrow}
\newcommand{\On}{\mathrm{On}} % ordinals
\DeclareMathOperator{\img}{im} % Image
\DeclareMathOperator{\Img}{Im} % Image
\DeclareMathOperator{\coker}{coker} % Cokernel
\DeclareMathOperator{\Coker}{Coker} % Cokernel
\DeclareMathOperator{\Ker}{Ker} % Kernel
\DeclareMathOperator{\rank}{rank}
\DeclareMathOperator{\Spec}{Spec} % spectrum
\DeclareMathOperator{\Tr}{Tr} % trace
\DeclareMathOperator{\pr}{pr} % projection
\DeclareMathOperator{\ext}{ext} % extension
\DeclareMathOperator{\pred}{pred} % predecessor
\DeclareMathOperator{\dom}{dom} % domain
\DeclareMathOperator{\ran}{ran} % range
\DeclareMathOperator{\Hom}{Hom} % homomorphism
\DeclareMathOperator{\End}{End} % endomorphism

% Things Lie
\newcommand{\kb}{\mathfrak b}
\newcommand{\kg}{\mathfrak g}
\newcommand{\kh}{\mathfrak h}
\newcommand{\kn}{\mathfrak n}
\newcommand{\ku}{\mathfrak u}
\newcommand{\kz}{\mathfrak z}
\DeclareMathOperator{\Ext}{Ext} % Ext functor
\DeclareMathOperator{\Tor}{Tor} % Tor functor
\newcommand{\gl}{\opname{\mathfrak{gl}}} % frak gl group
\renewcommand{\sl}{\opname{\mathfrak{sl}}} % frak gl group

% More script letters etc.
\newcommand{\SA}{\mathscr A}
\newcommand{\SB}{\mathscr B}
\newcommand{\SC}{\mathscr C}
\newcommand{\SD}{\mathscr D}
\newcommand{\SE}{\mathscr E}
\newcommand{\SF}{\mathscr F}
\newcommand{\SG}{\mathscr G}
\newcommand{\SH}{\mathscr H}
\newcommand{\OO}{\mathcal O}

%% Napkin commands
\newcommand{\prototype}[1]{
	\emph{{\color{red} Prototypical example for this section:} #1} \par\medskip
}
\newenvironment{moral}{%
	\begin{mdframed}[linecolor=green!70!black]%
	\bfseries\color{green!70!black}}%
	{\end{mdframed}}



%%fakesection Asymptote setup
\ifevanasy
	\ifevanpatchasy
		\usepackage{patch-asy}
	\else
		\usepackage{asymptote}
	\fi
	\begin{asydef}
		import olympiad;
		import cse5;
		pointpen = black;
		pathpen = black;
		pathfontpen = black;
		anglepen = black;
		anglefontpen = black;
		pointfontsize = 10;
		defaultpen(fontsize(10pt));
		size(8cm); // set a reasonable default
		usepackage("amsmath");
		usepackage("amssymb");
		settings.tex="latex";
		settings.outformat="pdf";
	\end{asydef}
\fi
\ifevanthm
	\usepackage{amsthm}
\fi

%%fakesection BEGIN MAIN SETUP
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\ifevansetup
	%%fakesection Set up author and date
	\ifevanauthor
		\AtBeginDocument{%
			\author{Evan Chen}
			\date{\today}
		}
	\fi
	%%fakesection Hyperref
	\ifevanpkg
		\PassOptionsToPackage{usenames,svgnames,dvipsnames}{xcolor}
		\usepackage{xcolor}
		\ifevanhref
			\usepackage[colorlinks=true]{hyperref}
			\hypersetup{urlcolor=RubineRed,linkcolor=RoyalBlue,citecolor=ForestGreen}
		\fi
		\usepackage[nameinlink]{cleveref}
	\fi

	%%fakesection New Theorem Styles -- mdbluebox, mdrecbox, mdinlinebox
	\ifevanmdthm
		\usepackage{thmtools}
		\usepackage[framemethod=TikZ]{mdframed}

		\mdfdefinestyle{mdbluebox}{%
			roundcorner = 10pt,
			linewidth=1pt,
			skipabove=12pt,
			innerbottommargin=9pt,
			skipbelow=2pt,
			linecolor=blue,
			nobreak=true,
			backgroundcolor=TealBlue!5,
		}
		\declaretheoremstyle[
			headfont=\sffamily\bfseries\color{MidnightBlue},
			mdframed={style=mdbluebox},
			headpunct={\\[3pt]},
			postheadspace={0pt}
		]{thmbluebox}

		\mdfdefinestyle{mdrecbox}{%
			linewidth=0.5pt,
			skipabove=12pt,
			frametitleaboveskip=5pt,
			frametitlebelowskip=0pt,
			skipbelow=2pt,
			frametitlefont=\bfseries,
			innertopmargin=4pt,
			innerbottommargin=8pt,
			nobreak=true,
			backgroundcolor=Salmon!5,
		}
		\declaretheoremstyle[
			headfont=\bfseries\color{RawSienna},
			mdframed={style=mdrecbox},
			headpunct={\\[3pt]},
			postheadspace={0pt},
		]{thmrecbox}

		\mdfdefinestyle{mdinlinebox}{%
			skipabove=8pt,
			linewidth=3pt,
			rightline=false,
			leftline=true,
			topline=false,
			bottomline=false,
			linecolor=green,
			backgroundcolor=green!2
		}
		\declaretheoremstyle[
			headfont=\bfseries\color{Cerulean},
			bodyfont=\normalfont\small,
			spaceabove=0pt,
			spacebelow=0pt,
			mdframed={style=mdinlinebox}
		]{thminlinebox}

		\newcommand{\listhack}{$\empty$\vspace{-2em}}
	\fi

	%%fakesection Theorem setup
	\ifevanthm
		\theoremstyle{plain}
		%Branching here: the option secthm changes theorems to be labelled by section
		\ifevanmdthm
			\ifevansecthm
				\declaretheorem[%
				style=thmbluebox,name=Theorem,numberwithin=section]{theorem}
			\else
				\declaretheorem[%
				style=thmbluebox,name=Theorem]{theorem}
			\fi
			\declaretheorem[style=thmbluebox,name=Lemma,sibling=theorem]{lemma}
			\declaretheorem[style=thmbluebox,name=Proposition,sibling=theorem]{proposition}
			\declaretheorem[style=thmbluebox,name=Corollary,sibling=theorem]{corollary}
			\declaretheorem[style=thmbluebox,name=Theorem,numbered=no]{theorem*}
			\declaretheorem[style=thmbluebox,name=Lemma,numbered=no]{lemma*}
			\declaretheorem[style=thmbluebox,name=Proposition,numbered=no]{proposition*}
			\declaretheorem[style=thmbluebox,name=Corollary,numbered=no]{corollary*}
		\else
			\ifevansecthm
				\newtheorem{theorem}{Theorem}[section]
			\else
				\newtheorem{theorem}{Theorem}
			\fi
			\newtheorem{lemma}[theorem]{Lemma}
			\newtheorem{proposition}[theorem]{Proposition}
			\newtheorem{corollary}[theorem]{Corollary}
			\newtheorem*{theorem*}{Theorem}
			\newtheorem*{lemma*}{Lemma}
			\newtheorem*{proposition*}{Proposition}
			\newtheorem*{corollary*}{Corollary}
		\fi
			
		%Def-style theorems
		\theoremstyle{definition}

		% This ought to be a real theorem, but would be too much italics
		\ifevanmdthm
			\declaretheorem[style=thmbluebox,name=Algorithm,sibling=theorem]{algorithm}
		\else
			\newtheorem{algorithm}[theorem]{Algorithm}
			\newtheorem*{algorithm*}{Algorithm}
		\fi

		\newtheorem{claim}[theorem]{Claim}
		\newtheorem{conjecture}[theorem]{Conjecture}
		\newtheorem{definition}[theorem]{Definition}
		\newtheorem{fact}[theorem]{Fact}

		\newtheorem{answer}[theorem]{Answer}
		\newtheorem{case}[theorem]{Case}
		\newtheorem{ques}[theorem]{Question}
		\newtheorem{exercise}[theorem]{Exercise}
		\newtheorem{problem}[theorem]{Problem}

		\newtheorem*{answer*}{Answer}
		\newtheorem*{case*}{Case}
		\newtheorem*{claim*}{Claim}
		\newtheorem*{conjecture*}{Conjecture}
		\newtheorem*{definition*}{Definition}
		\newtheorem*{fact*}{Fact}
		\newtheorem*{joke*}{Joke}
		\newtheorem*{ques*}{Question}
		\newtheorem*{exercise*}{Exercise}
		\newtheorem*{problem*}{Problem}


		\ifevanmdthm
			\declaretheorem[style=thmrecbox,name=Example,sibling=theorem]{example}
			\declaretheorem[style=thmrecbox,name=Example,numbered=no]{example*}
		\else
			\newtheorem{example}[theorem]{Example}
			\newtheorem*{example*}{Example}
		\fi

		% Remark-style theorems
		%\theoremstyle{remark}
		\newtheorem{note}[theorem]{Note}
		\newtheorem{remark}[theorem]{Remark}
		\newtheorem*{note*}{Note}
		\newtheorem*{remark*}{Remark}
		\newtheorem{abuse}[theorem]{Abuse of Notation}
		\newtheorem*{abuse*}{Abuse of Notation}
	\fi

	%%fakesection Fancy section and chapter heads
	\ifevancolorsec
		\@ifundefined{KOMAClassName}{}{
			\@ifundefined{chapter}{}{
				\addtokomafont{partprefix}{\rmfamily}
				\renewcommand*{\partformat}{\color{purple}
					\scalebox{2.5}{\thepart}\enlargethispage{2em}}
				\addtokomafont{chapterprefix}{\raggedleft}
				\RedeclareSectionCommand[beforeskip=0.5em]{chapter}
				\renewcommand*{\chapterformat}{\mbox{%
					\scalebox{1.5}{\chapappifchapterprefix{\nobreakspace}}%
					\scalebox{2.718}{\color{purple}\thechapter}\enskip}}
			}
			\renewcommand*{\sectionformat}%
				{\color{purple}\S\thesection\enskip}
			\renewcommand*{\subsectionformat}%
				{\color{purple}\S\thesubsection\enskip}
			\renewcommand*{\subsubsectionformat}%
				{\color{purple}\S\thesubsubsection\enskip}
			\KOMAoptions{numbers=noenddot}
			\usepackage[tocindentauto]{tocstyle}
			\usetocstyle{KOMAlike}
		}
	\fi


	%%fakesection Loads a bunch of useful packages (but allow disabling)
	\ifevanpkg
		\IfFileExists{von.sty}{\usepackage{von}}{}
		\usepackage{listings}
		\usepackage{mathrsfs}
		\usepackage{textcomp}
		\lstset{basicstyle=\footnotesize\ttfamily,
			numbers=left,
			numbersep=5pt,
			numberstyle=\tiny,
			keywordstyle=\bfseries,
			% title=\lstname,
			showstringspaces=false,
			tabsize=4,
			frame=single,
			keywordstyle=\bfseries\color{blue},
			commentstyle=\color{green!70!black},
			identifierstyle=\color{green!20!black},
			stringstyle=\color{orange},
			breaklines=true,
			breakatwhitespace=true,
			frame=none
		}
		\usepackage[shortlabels]{enumitem}
		\usepackage[obeyFinal,textsize=scriptsize,shadow]{todonotes}
		\usepackage{textcomp}
		% Tiny tiny optimizations:
		\usepackage{mathtools}
		\usepackage{microtype}
	\fi

	%%fakesection \maketitle configuration
	\ifevantitling
	%If we have titling...
		\usepackage{titling}
		\@ifundefined{KOMAClassName}{}{
			\newcommand{\thesubtitle}{}
			\@ifundefined{chapter}{
				% No \chapter, so small style
				\renewcommand{\subtitle}[1]{%
					\renewcommand{\thesubtitle}{#1}
					\pretitle{\begin{center}\bfseries \sffamily \Large}
					\posttitle{\\ {\normalsize \thesubtitle} \end{center}\vspace{\posttitledrop}}
				}
			}{
				% \chapter exists, so large style
				\renewcommand{\subtitle}[1]{%
					\renewcommand{\thesubtitle}{#1}
					\pretitle{\begin{center}\bfseries \sffamily \Huge}
					\posttitle{\\ {\Large \thesubtitle} \end{center}\vspace{\posttitledrop}}
				}
			}
		}
		\newlength{\posttitledrop}
		\newlength{\postauthordrop}
		\@ifundefined{chapter}{
			% No \chapter, so small style
			\setlength{\posttitledrop}{-0.7em}
			\setlength{\postauthordrop}{-1.2em}
			\pretitle{\begin{center}\bfseries \sffamily \Large}
			\posttitle{\end{center}\vspace{\posttitledrop}}
			\preauthor{\begin{center} \scshape}
			\postauthor{\end{center}\vspace{\postauthordrop}}
			\predate{\begin{center}\small}
			\postdate{\end{center}}
		}{
			% \chapter exists, so large style
			\setlength{\droptitle}{-8cm}
			\setlength{\posttitledrop}{1em}
			\setlength{\postauthordrop}{0.5em}
			\pretitle{\begin{center}\bfseries \sffamily \Huge}
			\posttitle{\end{center}\vspace{\posttitledrop}}
			\preauthor{\begin{center} \scshape \LARGE}
			\postauthor{\end{center}\vspace{\postauthordrop}}
			\predate{\begin{center} \Large}
			\postdate{\end{center}}
		}
	\fi

	%%fakesection Commutative diagrams support
	\ifevandiagrams
		\usepackage{diagrams}
		\newarrow{Inj}C--->
		\newarrow{Surj}----{>>}
		\newarrow{Proj}----{>>}
		\newarrow{Embed}>--->
		\newarrow{Incl}C--->
		\newarrow{Mapsto}|--->
		\newarrow{Isom}<--->
		\newarrow{Dotted}....>
		\newarrow{Dashed}{}{dash}{}{dash}>
		\newarrow{Line}-----
		\usepackage{tikz-cd}
		\usetikzlibrary{decorations.pathmorphing}
		\tikzcdset{row sep/normal=3.14em,column sep/normal=3.14em}
	\fi

	%%fakesection Page Setup
	\ifevanfancy
		\@ifundefined{KOMAClassName}
		{
			\usepackage{fancyhdr}
			\setlength{\headheight}{0.75in}
			\setlength{\oddsidemargin}{0in}
			\setlength{\evensidemargin}{0in}
			\setlength{\voffset}{-1.0in}
			\setlength{\headsep}{10pt}
			\setlength{\textwidth}{6.5in}
			\setlength{\headwidth}{6.5in}
			\setlength{\textheight}{8.75in}
			\setlength{\parskip}{1ex plus 0.5ex minus 0.2ex}
			\setlength{\footskip}{0.3in}
			\ifevantitling
				\addtolength{\posttitledrop}{0.4em}
				\addtolength{\postauthordrop}{0.2em}
			\fi
			\ifevanhdr
				\renewcommand{\headrulewidth}{0.5pt}
				\renewcommand{\footrulewidth}{0.0pt}
				\pagestyle{fancy}
				\ifevantitling \lhead{\theauthor} \else \lhead{Evan Chen} \fi
				\chead{}
				\rhead{\nouppercase{\leftmark}}
				\lfoot{}
				\cfoot{\thepage}
				\rfoot{}
			\fi
		}
		{
			\usepackage[headsepline]{scrlayer-scrpage}
			\renewcommand{\headfont}{}
			\addtolength{\textheight}{3.14cm}
			\setlength{\footskip}{0.5in}
			\setlength{\headsep}{10pt}
			\ifevantitling
				\ihead{\footnotesize\textbf{\theauthor} (\thedate)}
				\else
				\ihead{\footnotesize\textbf{Evan Chen} (\thedate)}
			\fi
			\automark{section}
			\chead{}
			\ifevantitlemark
				\ohead{\footnotesize\textbf{\thetitle}}
			\else
				\ohead{\footnotesize\textbf{\headmark}}
			\fi
			\cfoot{\pagemark}
		}
	\fi

	%%fakesection Chinese support
	\ifevanchinese
		\usepackage[encapsulated]{CJK}
		\usepackage{ucs}
		\usepackage[utf8x]{inputenc}
		\newenvironment{bsmi}{\begin{CJK}{UTF8}{bsmi}}{\end{CJK}}
		\newcommand{\cn}[1]{\begin{bsmi}#1\end{bsmi}}
		\AtBeginDocument{\begin{CJK}{UTF8}{bsmi}}
		\AtEndDocument{\end{CJK}}
	\fi

	%%fakesection Hints
	\ifevanhints
		\usepackage{answers}
		\Newassociation{hint}{hintitem}{hints}
		\renewcommand{\solutionextension}{out}
		\Opensolutionfile{hints}
		\newcommand{\makehints}{\Closesolutionfile{hints}\input{hints.out}}
	\fi
%%fakesection END MAIN SETUP
\fi